Maintenance & Repair 350Z up keep and diagnosing/fixing problems

2007 350z Idle Surging (I know..)

Old 01-03-2016, 08:29 AM
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I know this is an old thread, but I have been dealing with this problem for a few weeks now on my 2007 hr. I have replaced the ecm with a used one and replaced the throttle bodies with oem used as well. Problem is still there. Ive done everything; attempted idle relearn over 100 times even using the nissandatascan android app, lowered rpm by disconnecting injectors, clogging intakes, unbolting tb's. Nothing works. It is my understanding now that as carbon buildup accumulates in the throttle bodies, the ecm compensates by gradually adjusting the butterfly angle to keep the idle within the correct range. When cleaned, the ecm is now compensating for carbon buildup that is no longer there. This leads me to believe that the throttle bodies have nothing to do with it, but rather its the ecm that is just very stubborn to relearn the correct position of the butterfly valve.

I repeatedly asked my local dealer about an ecu update/reprogram to which they repeatedly responded "no we don't have anything like that." So I did a little digging and came across nissan's techinfo webpage. On this page they clearly express that all of their ecms are easily reprogrammable, the files can even be downloaded for $20 on their website. Turns out there is both a technical service bulletin and a software revision for the 2007 HR (EV11A to EV11C). Something the morons at the dealer didn't even attempt to research.

So I will be going to a dealer that is a little more knowledgeable and bring them my downloaded reprogram file and see what happens. My bet is that once the ecm is wiped clean and reprogrammed, the base butterfly position will be reset and this issue will be gone. I will be sure post my results.

This simple TB cleaning has turned out to be a complete nightmare so I hope this info helps those with the same issue. Never has the saying "if it aint broke, don't fix it." ever been more true.

Last edited by aredd2009; 01-04-2016 at 08:17 PM.
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Old 01-04-2016, 09:22 PM
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So just to update, I was able to finally get the idle air relearn to take therefore it was unnecessary for me to get the ecm reprogrammed at the dealer. This may still be an option for some.

My best advice for anyone who may have this issue is before buying any parts or going to the dealer, buy a bluetooth OBDII scanner and get the nissan data scan app (NDSIII) for android (free for lite version). The bluetooth device that worked for me was the BAFX OBDII scanner from amazon ($23).

With this scanner/app combination you can carry out the idle air volume relearn at the touch of a button rather than doing the pedal dance or going to the dealer. This will be quite helpful as you very well may be attempting the manual relearn process hundreds of times without knowing for sure if your timing was correct.

What eventually worked for me was I replaced the TB's with used ones from a salvage yard. Though I replaced the tb's, I am not entirely sure if the tb's were the culprit. When I first installed the used Tb's, the idle surging remained and the idle relearn would not complete. So I put the original tb's back on. Nothing changed and again the idle relearn wouldn't complete. So I decided to try something different the third time and instead left the battery connected when installing the used tb's. After doing this, the idle was much lower and wasn't surging as it was before. The idle however still remained around 1000 rpm in neutral. I then attempted the idle relearn and it worked. FINALLY.

So what I recommend is before buying expensive parts or making a trip to the dealer, try unplugging the wire harnesses from the TB's while the battery is still connected and the car is off. Leave them unplugged for a few minutes and plug them back in. I believe that this perhaps lets the ecm know that they are being replaced/removed and therefore the ecm is more likely to accept a relearn. After plugging everything back in, carry out the released pedal position learning and the closed tb position learning. Start the car and warm it up. Make sure all the parameters listed in the service manual are met.

Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific range. It must be performed under any of the following conditions:
Each time electric throttle control actuator or ECM is replaced.
Idle speed or ignition timing is out of specification.
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are missed for even a moment.
Battery voltage: More than 12.9V (At idle)
Engine coolant temperature: 70 - 100C (158 - 212F)
Park/neutral position (PNP) switch: ON
Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine is started, the headlamp will not be illuminated.
Steering wheel: Neutral (Straight-ahead position)
Vehicle speed: Stopped
Transmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until “ATF TEMP SE 1” in “DATA MONITOR” mode of “A/T” system indicates less than 0.9V.
For A/T models without CONSULT-II and M/T models, drive vehicle for 10 minutes.

These parameters (excluding auto trans temp) can be easily monitored using NDSIII therefore you will know the best time to carry out the relearn.I recommend not letting the coolant temp get higher than 195 degrees F because the cooling fans may turn on which will cause the relearn to time out. Be sure that there are no dtc's stored in the ecm, again these can be read and cleared in the NDSIII app. If there are dtc's, clear them, and then turn the car off and start it back up again. Just know that every time you turn the car off the NDSIII app will lose its connection to your obd device so you will have to reconnect it.

After all the parameters are met, attempt the relearn process using the app. If the counter on the app goes more than 500, the relearn more than likely will not take (should take around 20 seconds). If this happens simply let it time out, or better, reconnect the bluetooth scanner on the "info" screen and try the relearn again.

If this process doesn't work then it is possible that your tb's are bad. By "bad" I mean too clean; letting too much air into the engine bringing up the rpm's which in turn causes the ecm to cut the fuel to bring the idle back down. The relearn will more than likely never take during this condition. I would try an ecm reprogram (cheaper) before replacing throttle bodies and if that doesn't work source some used tb's (dirty ones haha) so the idle will be low enough to carry out the relearn.

Last edited by aredd2009; 01-04-2016 at 09:29 PM.
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Old 03-15-2019, 01:54 PM
Luke Tabayoyong
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Default High idle/Idle surge after cleaning throttle bodies

Regarding people with high idle/idle surge issue w/ 07'350z after cleaning the throttle bodies. the issue is not bad throttle bodies. Its the ECU!!....i stumbled across a tuner based in Concord CA named Eugene Turkov that found a way to fix the issue with the ECU. Decided to send my ECU out to him in hopes he could solve the issue. Based on his previous experience with the problem he said the latest firmware update will NOT fix the problem. The fix was upgrading the original ECU to a firmware from a similar 2008 model. My car is now running healthier than when i purchased it 4 years ago! Let me know if any of you need his info!
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